1. Field of the Invention
Example embodiments generally relate to a transfer-fixing device and an image forming apparatus, and more particularly, to a transfer-fixing device for transferring and fixing a toner image on a recording medium and an image forming apparatus including the transfer-fixing device.
2. Description of the Related Art
Related-art image forming apparatuses, such as copiers, facsimile machines, printers, or multifunction printers having at least one of copying, printing, scanning, and facsimile functions, typically form an image on a recording medium according to image data. Thus, for example, a charger uniformly charges a surface of an image carrier; an optical writer emits a light beam onto the charged surface of the image carrier to form an electrostatic latent image on the image carrier according to the image data; a development device supplies toner to the electrostatic latent image formed on the image carrier to make the electrostatic latent image visible as a toner image; a transfer device transfers the toner image formed on the image carrier onto an intermediate transfer member; a transfer-fixing device transfers and fixes the toner image from the intermediate transfer member onto a recording medium, thus forming the image on the recording medium.
One benefit of such transfer-fixing device is its ability to transfer and fix the toner image properly even on rough recording media. Specifically, the transfer-fixing device applies heat to the toner image to melt and fix the toner image on the recording medium concurrently with transferring the toner image formed on the intermediate transfer member onto the recording medium. Accordingly, even when the rough recording medium passes over the intermediate transfer member and slight gaps are formed between the recording medium surface and the intermediate transfer member due to surface asperities of the recording medium, the heat applied by the transfer-fixing device to the toner image softens and melts toner of the toner image into viscous blocks that are then transferred onto the recording medium. By contrast, in image forming apparatuses that include separate transfer and fixing devices, in which the fixing device fixes the toner image after the transfer device transfers the toner image from the intermediate transfer member onto the rough recording medium, abnormal discharge may occur in the slight gaps formed between the surface of the rough recording medium and the intermediate transfer member. Consequently, the toner image may not be transferred from the intermediate transfer member onto the rough recording medium properly, resulting in formation of a faulty, rough image.
However, the intermediate transfer member of the transfer-fixing device is long and thick, thus degrading heating efficiency for heating the intermediate transfer member and increasing energy consumption. Moreover, the intermediate transfer member needs to be cooled after the transfer-fixing process to prevent the heated intermediate transfer member from damaging the image carrier contacting the intermediate transfer member. Such repeated heating and cooling processes may increase energy consumption.